The present invention relates among other things to a communication system where the transmission of signals between different nodes takes place via company nodes (master nodes) that allocates permission to transmit to the respective mobile customer (slave) nodes in given time slots. The invention also relates to a device in the form of a mobile data and telecommunications network within a predetermined geographical area, for example within a company, factory, hospital, etc, and working with first functions, for example in the form of company (master) functions and second functions, for example in the form of communication functions and/or customers (slave) functions, established by means of fixed and/or movable nodes and/or mobile units. In addition, the invention relates to an arrangement with a mobile telecommunications and/or data network located in a geographical area, which network comprises company (master) functions and mobile customer (slave) functions.
A well-established way of carrying out wireless communication is to set-up a cell with a base station that has a number of transmitting and receiving stations within its area. These communicate with each other via the base station, that is the transmitting station has an “up” link to the base station and the receiving station has a “down” link. A well-known system with this construction is Bluetooth. The invention is described using Bluetooth as an example, but can also be implemented in all similar systems.
Bluetooth allows a master to provide service to up to seven slaves that are active. An unlimited number of slaves can be put in Park Mode and can either be activated by the master or activate themselves. A master can have a very restricted range. It is usually a question of a restriction to approximately 10 m, but technically a considerably larger range can be achieved. Bluetooth provides standardized profiles that can be used in the present invention, for example, K1-6 and K9 are relevant.
It is desirable to be able to use Bluetooth standard units as headsets, PCs, mobile telephones, etc, in order to provide service from various sources, for example companies, within their geographical area, for example, within a department store, a petrol station, etc. A problem is that there are many customers in the area, and that each node in the company's network can only handle at most seven customers at a time. This means that it is necessary to have many masters within the area, and as these utilize the frequency range independent of each other, there is an inefficient utilization of the local bandwidth. In addition, the customers, that is the Bluetooth slaves, must re-synchronize or rather execute handshakings frequently to new masters. Said handshaking procedures are time consuming in Bluetooth.
Solution
The company arranges a Bluetooth network in the usual way and sets itself up as the master in the pico-network. By this means, full control is obtained of the bandwidth utilization for the slaves connected to the pico-network. By synchronizing for time and frequency all the master nodes belonging to the company within the area, these can appear to be one and the same master to all the slaves within the area.